In order to obtain a better understanding of the neurochemical bases for behavior modification resulting from environmental stresses, we have undertaken studies concerned with (a) alterations in levels and characteristics of enzymes which, because they are rate limiting, may provide critical regulation of neurotransmitter levels (e.g. monoamine oxidase, tyrosine hydroxylase, etc.) and (b) the extents to which neurotransmitter concentrations may be modulated or altered in those parts of the central nervous system which are though to be involved in behavior regulation. In the studies involving monamine oxidase (MAO), we are investigating the behavioral consequences of inhibiting MAO types A and B as well as several of the characteristics of MAO types A and/or B responsiveness to various substrates and inhibitors.